What You Need To Know About Universal Windows Apps

The transition

It is a transition period for Microsoft developers. The development stacks for making Windows Phone 8 and Windows 8 applications have been different for quite a while. Windows Phone 8 uses the Silverlight stack whereas Windows 8+ uses the Windows Runtime. With //build 2014, Microsoft converged Windows Phone with Windows Store apps into a single platform - the Windows Runtime.

There are many Windows Phone 8 devices still available on the market that will not be able to run the new Windows Phone 8.1 update so Microsoft introduced Windows Phone Silverlight 8.1. In short it enables Windows Phone 8 developers some of the new features available in the Windows Runtime.

Below is an attempt to summarize what each platform offers and what is available to Telerik developers.

What is Windows Runtime?

The Windows Runtime enables developers to build apps that can target each form factor in the family of Windows 8.1 devices. The Windows Runtime is a combination of Windows 8.1 and Windows Phone 8.1. Sharing code between Windows 8 and Windows Phone 8 apps has been difficult. A lot of scenarios involving the UI layer, push notifications and tiles required different approaches which made code reuse tough. Windows Phone 8.1 now uses the same development stack as Windows 8.1 which means that developers can build applications that share the same application code and UI and can target both Windows Phone 8.1 and Windows 8.1 devices.

If a developer chooses to go with a Universal App, Visual Studio will output a solution that has 3 projects:

Windows 8.1 - a project that represents the version of your app that targets larger devices - tablets, desktops and larger form factors.

Windows Phone 8.1 - a project that represents the version of your app that targets Windows Phone 8.1 devices.

Shared project. The shared project is referenced both by the Windows 8.1 and Windows Phone 8.1 projects. This means that everything included in the Shared project is available in the Windows 8.1 and Windows Phone 8.1 projects.

Targeting both platforms is not always necessary. If a developer wants to build a phone application only, he can do so by creating only a Windows Phone 8.1 project.

What is Windows Phone Silverlight 8.1?

Windows Phone Silverlight 8.1 is a framework that was released alongside the new Windows Runtime. With Windows Phone Silverlight 8.1 developers can make their existing Windows Phone 7/8 apps available only on Windows Phone 8.1 devices.

Under the hood of Windows Phone Silverlight 8.1

Windows Phone Silverlight 8.1 is part of the Silverlight stack and was released alongside the new Windows Runtime. With Windows Phone Silverlight 8.1 developers can make their existing Windows Phone apps available on all Windows Phone 8.1 devices. All they have to do is right click on an existing Windows Phone project in Visual Studio and choose the option Upgrade to Windows Phone 8.1.

Windows Phone Silverlight 8.1 offers certain opportunities to developers. A developer can take advantage of Windows Phone 8.1 features and target Windows Phone 8.1 devices without the need to create a new Windows Universal app.

Windows Phone Silverlight 8.1 has certain drawbacks.

Developers don’t have to modify anything in the application code and UI, but they’ll still need to repackage and republish their app which calls for additional work.

Not all Windows 8.1 features are available.

Applications can run only on Windows Phone 8.1 devices. If the developer wants to support larger devices he’ll have to create a separate Windows 8/Windows 8.1. If the developer wants to create a Windows 8.1 counterpart of his app he will have to use the Windows Runtime. This means that he cannot reuse most of his application code and UI. In addition, the developer will have to maintain and distribute 2 separate applications.

What is the difference between Windows Runtime and Windows Phone Silverlight 8.1?

The main difference between Windows Runtime and Windows Phone Silverlight 8.1 is the development stack each technology is using.

Developers should be aware that Windows Phone 8 and Windows Phone Silverlight 8.1 use the old Silverlight XAML stack whereas Windows Phone 8.1 and Windows 8.1 use the new Windows Runtime stack.

What does Telerik offer?

Telerik has several products that native Windows developers can use – UI for Windows Phone 8, UI for Windows 8, and UI for Windows Universal. The Q&A section below should explain which Telerik products are available for the two development stacks.

Can I reference UI for Windows Universal in a Windows Phone Apps project (Windows Phone 8.1)?
Yes. Developers can use all Universal and Windows Phone 8.1 specific controls in their Windows Phone 8.1 project.

Can I reference UI for Windows Universal in a Windows Apps project (Windows 8.1)?
Yes. You will be able to use all Universal and Windows 8.1 specific controls in your Windows 8.1 project. This means that you can use UI for Windows 8 in your Windows 8.1 project.

Can I use UI for Windows Phone 8 to build Windows Phone 8.1 apps?
Yes. UI for Windows Phone 8 is part of the Silverlight development stack. Developers have the opportunity to create a Windows Phone 8 app and port it using Windows Phone Silverlight 8.1.

Can I use UI for Windows Phone 8 to build Windows Universal apps?
No. UI for Windows Phone 8 uses the Silverlight stack whereas the Windows Universal apps use the new Windows Runtime.

Can I use UI for Windows 8 to build Windows Universal apps?
In a way. UI for Windows 8 can be referenced only in stand-alone Windows 8.1 projects and the Windows 8.1 part of a universal application.

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